The circles wouldn't work on a properly screened vinyl sticker unless you posterize the image to two colours, as those gradients would require to be halftoned, which at the usual resolution of a proper vinyl sticker (about 55dpi) would look awful. I've flattened it in photoshop and it looks ok without the gradient effect. Of course if you're printing straight off a laser printer it might turn out ok, but vinyl stickers are the way to go, they last yeeears...
Point aside, it looks ok to me
